During the summer months of 1985, 1,298 adult mosquitoes comprising 21 species and 7 genera were collected in Macon County, Alabama. Mosquitoes were collected from four sections of the county with CO2-baited light traps. Spiroplasma cultures were isolated from two pools of 24 and 25 Aedes fulvus pallens, one pool of 22 Anopheles punctipennis and one pool of 7 Culex nigripalpus. Electron microscopic studies of the isolates revealed helical, wall-less cells.